Heat exchanger

ABSTRACT

The invention relates to a heat exchanger ( 1 ) for indirect heat transfer between a first medium (F 1 ) and a second medium (F 2 ), comprising: a shell ( 2 ) which has a shell space ( 3 ) for receiving the first medium (F 1 ), a heat transfer block ( 4 ) which is disposed in the shell space ( 3 ) and which during correct operation is surrounded by the first medium (F 1 ), wherein the heat transfer block ( 4 ) is designed to cool the second medium (F 2 ) against the first medium (F 1 ), such that a gaseous phase of the first medium (G 1 ) forms in the shell space ( 3 ). According to the invention a collecting channel ( 5 ) located in the shell space ( 3 ) is provided for drawing off the gaseous phase of the first medium (G 1 ) from the shell space ( 3 ).

The invention relates to a heat exchanger according to the preamble of claim 1.

Such a heat exchanger is featured in “The Standards of The Brazed Aluminium Plate-Fin Heat Exchanger Manufacturer's Association (ALPEMA)”, third edition, 2010, page 67 in FIG. 9-1. It has a shell which encloses a shell space, and also at least one heat transfer block (“core”) which is arranged in the shell space and designed as a plate heat exchanger. Such a design of a heat exchanger is also referred to as a “core-in-shell” or “block-in-shell” heat exchanger.

With such a heat exchanger, a first medium, which forms a bath enveloping the heat transfer block during operation of the heat exchanger and rises from the bottom upwards (thermosiphon effect) in the heat transfer block (along the vertical), can especially be brought into a direct heat transfer with a second medium (e.g. a gaseous phase which is to be liquefied or a liquid phase which is to be cooled) which is preferably conducted in the heat transfer block in counterflow or crossflow to the first medium. A gaseous phase of the first medium which emerges during this collects in the shell space above the heat transfer block and is extracted via at least one outlet connector provided on the shell and is perhaps fed to further process steps via an (external) collecting channel which is provided outside the shell.

As a result of this type of extraction of the gaseous phase, there develops in the shell space a heterogeneous velocity field of the gaseous phase heading towards the outlet connector which impairs the quality of the gas-liquid separation in the shell space. This effect can be counteracted by a variation of the number or the size of the outlet connectors but only to a limited extent, particularly as the flow characteristics in the external collecting channel also react to the velocity field of the gaseous phase in the shell space. Furthermore, the outlet connectors are pressure-resistant component parts of a (“core-in-shell”) heat exchanger of the type referred to in the introduction and are therefore constructionally expensive which entails increased production costs in the case of a plurality of outlet connectors. Furthermore, by fixing the outlet-connector position on the upper side of the shell a degree of freedom is taken away during the construction of the surrounding components (e.g. cold box, field tubing).

Starting from here, the invention is therefore based on the object of providing a heat exchanger which is improved with regard to the aforesaid problems.

This problem is solved by means of a heat exchanger having the features of claim 1.

Accordingly, it is provided that the collecting channel is located in the shell space and is designed for extracting the gaseous phase from the shell space.

According to one embodiment of the invention, provision can also be made in the shell space for a plurality of heat transfer blocks or plate heat exchangers which can be operated in parallel or in series, for example.

Such plate heat exchangers as a rule have a multiplicity of plates arranged in parallel with each other and form a large number of heat exchange passages for media which participate in the exchange of heat. A preferred embodiment of a plate heat exchanger has a multiplicity of corrugated plates (so-called fins) which in each case are arranged between two parallel separating plates of the plate heat exchanger, wherein the two outermost layers of the plate heat exchanger are formed by cover plates. In this way, a large number of parallel channels or a heat exchange passage, through which a medium can flow, are formed between each two separating plates or between a separating plate and a cover plate on account of the fins which are arranged between them in each case. In adjacent heat exchange passages flowing media can therefore indirectly exchange heat. Towards the sides, between each two adjacent separating plates or between a cover plate and the adjacent separating plate, provision is preferably made for sealing strips (so-called side bars) for closing off the respective heat exchange passage. The cover plates, separating plates, fins and side bars are preferably produced from aluminum and are soldered together in an oven, for example. Via corresponding headers with connectors, media can be introduced into the heat exchange passages or extracted from these.

The shell of the heat exchanger can especially have an encompassing (circular) cylindrical wall which in a design-specified arranged state of the heat exchanger is preferably oriented so that the longitudinal axis (cylinder axis) of the wall or of the shell extends along the horizontal. Connected to that wall, on the end face, the shell preferably has mutually opposite walls which extend transversely to the horizontal or to the longitudinal axis.

Said collecting channel for extracting the gaseous phase of the first medium is preferably connected (e.g. via a pipe) in a flow-conducting manner to an outlet connector, which is especially arranged on an upper side of the shell, so that the gaseous phase of the first medium can be extracted from the shell space via those outlet connectors.

In one embodiment of the invention, it is provided that the collecting channel extends along a direction of extension which is oriented parallel to the longitudinal axis (cylinder axis) of the shell or along the horizontal, and in this case preferably has a tubular (circular) or a box-shaped (rectangular) cross section transversely to said direction of extension (longitudinal axis).

The collecting channel (with regard to a design-specified arranged state of the heat exchanger) is preferably arranged in the shell space along the vertical above the liquid level of the first medium or above the heat transfer block so that the rising (from the heat transfer block) gaseous phase of the first medium meets with the collecting channel.

The collecting channel preferably has a wall which encloses an interior space of the collecting channel in which the gaseous phase can flow towards said outlet connector. In this case, that section of each wall of the collecting channel which points towards an upper side of the heat exchanger or points upwards along the vertical is referred to as the upper side of the collecting channel, and the oppositely disposed section of the wall of the collecting channel which points towards the lower side of the heat exchanger, correspondingly constitutes the lower side of the collecting channel. The upper and lower sides of the collecting channel are preferably interconnected by sidewalls of the collecting channel which are extended along the longitudinal axis of the shell. At the ends, the collecting channel is preferably delimited by mutually opposite end faces which in each case interconnect the upper side, the lower side and the sidewalls.

A variant of the invention furthermore provides that one or more of the aforesaid sections of the wall of the collecting channel can be formed by the shell of the heat exchanger. The upper side of the collecting channel or the upper side of the wall of the collecting channel is preferably formed by the shell. The sidewalls and end faces are therefore correspondingly attached to the shell away from the shell space.

For extracting the gaseous phase, the collecting channel preferably has a multiplicity of inlet openings which are especially formed on the lower side (bottom) of the collecting channel and, if applicable, also on the mutually opposite sidewalls of the collecting channel. In this case, the inlet openings which are formed on the bottom of the collecting channel are preferably of a slot-like design, whereas inlet openings provided on the sidewalls preferably have a circular contour (e.g. holes).

It is preferably provided that the spacings of adjacent inlet openings, and particularly the spacings of the inlet openings provided on the lower side, decrease towards the respective end face of the collecting channel. That is to say, the two adjacent inlet openings which are located closer to one of the end faces of the collecting channel, preferably have a smaller spacing in relation to each other along the direction of extension of the collecting channel than two adjacent inlet openings which are arranged more towards the middle of the collecting channel (with regard to the direction of extension).

The number, distribution, size and/or shape of the inlet openings is, or are, preferably selected so that the velocity field of the gaseous phase of the first medium in the collecting channel is established as uniformly as possible with regard to value. Furthermore, according to one aspect of the invention the cross-sectional area (and contour, if applicable) of the collecting channel (in a plane perpendicular to the direction of extension of the collecting channel) is selected in such a way that a flow field of the gaseous phase of the first medium which is as uniform as possible is established in the collecting channel and in the shell space. This is preferably assisted by a widening/enlargement of the cross section of the collecting channel towards the outlet connector and/or by a defined arrangement, shape and size of the inlet openings on the collecting channel.

Furthermore, the shell can naturally also have a multiplicity of outlet connectors which can be connected to a collecting channel, as previously described, or possibly to a plurality of collecting channels of the previously described type.

The positions, dimensions and orientations of these collecting channels are preferably selected in this case so that the velocity field of the gaseous phase of the first medium in the shell space and in the respective collecting channel is established as uniformly as possible with regard to value.

Furthermore, the at least one outlet connector (or even a plurality of outlet connectors) can be arranged according to the invention on an upper, a lower and a side section of the encompassing wall of the shell or on one of the end-face walls of the shell.

Further details and advantages of the invention shall be explained in more detail by the following figure descriptions of exemplary embodiments with reference to the figures. Advantageous embodiments of the invention are furthermore disclosed in the dependent claims.

In the drawing:

FIG. 1 shows a sectional view of a heat exchanger according to the invention;

FIG. 2 shows a further sectional view of the heat exchanger according to FIG. 1; and

FIG. 3 shows a sectional view of a collecting channel of the heat exchanger according to FIGS. 1 and 2.

FIG. 1, in conjunction with FIGS. 2 and 3, shows a heat exchanger 1 which has a transversely lying, (circular) cylindrical shell 2 which delimits a shell space 3 of the heat exchanger 1. The shell 2 in this case has an encompassing, cylindrical wall 14 which is delimited on the end faces by two mutually opposite walls 15.

A heat transfer block 4 is arranged in the shell space 3 which is enclosed by the shell 2. In this case, it can be a plate heat exchanger which provides a plurality of parallel heat exchange passages.

The plate heat exchanger 4 has in this case a multiplicity of corrugated plates (so-called fins) which are arranged in each case between two flat separating plates of the plate heat exchanger 4. In this way, a large number of parallel passages or one heat exchange passage are/is formed between each two separating plates (or one separating plate and one cover plate, see below), through which the respective medium can flow. The two outermost layers are formed by cover plates of the plate heat exchanger, with sealing strips (so-called “side bars”) being provided towards the sides between each two adjacent separating plates or between separating plates and cover plates.

The shell space 3 is filled with a first medium F1 during an operation of the heat exchanger 1 so that a liquid phase L1 of the first medium F1 forms a bath which envelops the heat transfer block or plate heat exchanger 4, wherein a gaseous phase G1 of the first medium F1 which develops during operation can collect in the shell space 3 above the liquid phase L1.

The first medium (liquid phase L1) F1 can rise in the heat transfer block 4 (in associated heat exchange passages) and in the process is partially evaporated, as a result of indirect heat transfer, by means of a second medium F2 which is to be cooled and which, for example, is conducted in crossflow to the first medium F1 in associated heat exchange passages of the heat transfer block 4. The gaseous phase G1 of the first medium F1 which results during this can discharge at an upper end of the block 4 and rises in the shell space 3 of the heat exchanger 1 at a determined velocity v.

The second medium F2 is directed via a suitable inlet O (e.g. via a connector on a header) into the heat transfer block or plate heat exchanger 4 and after passing through the associated heat exchange passages is extracted from the block 4 via an outlet O′ (e.g. via a corresponding header and a connector which is connected thereto).

Arranged on the upper side 8 of the heat exchanger 1, on an inner side 2 a of the shell 2 facing the shell space 3, is a box-shaped collecting channel 5 which extends along a direction of extension 7. The collecting channel 5 in this case is especially of an elongated design and correspondingly has a greater spread along the direction of extension 7 than transversely to that direction of extension 7.

The collecting channel 5 furthermore has a wall W which delimits an interior space I of the collecting channel 5 and through which the gaseous phase G1 of the first medium F1 is extracted from the shell space 3. The wall W particularly has an upper side 9 which in the present case is formed by the shell 2, and also two sidewalls 11, projecting therefrom, which extend along the direction of extension 7 and are interconnected via a bottom (lower side) 10 of the collecting channel 5 which lies opposite the upper side 9. Furthermore, the collecting channel 5 or its wall W has two end faces 11 a, 11 b which lie opposite each other along the direction of extension 7.

For extracting the gaseous phase G1 of the first medium F1 from the shell space 3, provision is now made on the sidewalls 11 and/or on the lower side 10 of the collecting channel 5 for slot-like inlet openings 12 (slot-like inlet openings on the lower side 10 in the present case) through which the gaseous phase G1 can enter the collecting channel 5. The inlet openings 12 in this case are arranged next to each other along the direction of extension 7, wherein the distance between adjacent inlet openings 13 along the direction of extension 7 preferably decreases in each case from the outlet connector 6 towards the two end faces 11 a, 11 b of the collecting channel 5. The longitudinal axes of these inlet openings 12 extend in this case transversely to the direction of extension 7 of the collecting channel 5 in each case.

Furthermore, provision is made on the sidewalls 11 and/or on the lower side 10 of the collecting channel 5 in each case for circular inlet openings 13 (circular inlet openings 13 on the side walls 11 in the present case) which are also arranged next to each other along the direction of extension 7. Here also, the distance between adjacent inlet openings 12 along the direction of extension 7 preferably decreases in each case from the outlet connector 6 towards the two end faces 11 a, 11 b of the collecting channel 5.

The collecting channel 5 is also connected to an outlet connector 6 of the shell 2 which opens into the upper side 9 of the collecting channel 5 so that the gaseous phase G1 of the first medium F1 which has made its way via the inlet openings 12, 13 into the interior space I of the collecting channel 5 can be extracted from the collecting channel 5 via the outlet connector 6.

The outlet connector 6 is arranged along the direction of extension 7 preferably in the middle on the collecting channel 5, wherein the lower side 10 of the collecting channel 5 preferably has two sections 10 a, 10 b which slope downwards towards the outlet connector 6 and meet preferably beneath said outlet connector 6.

The cross section of the collecting channel 5 increases (widens) in each case from the end faces 11 a, 11 b of the collecting channel 5 in the direction of the outlet connector 6 in order to achieve a velocity field v of the gaseous phase G1 of the first medium F1 which is as homogeneous as possible in the collecting channel 5 (and in the shell space 3).

LIST OF DESIGNATIONS

 1 Heat exchanger  2 Shell  2a Inner side  3 Shell space  4 Heat transfer block  5 Collecting channel  6 Outlet connector  7 Direction of extension  8 Upper side of the shell  9 Upper side of the collecting channel 10 Lower side of the collecting channel 10a, 10b Sections of the lower section 11 Sidewalls of the collecting channel 11a, 11b End faces 12 Slot-like inlet openings 13 Circular inlet openings 14 Encompassing wall of the shell 15 End-face walls of the shell 16 Lower side of the shell F1 First medium G1 Gaseous phase of the first medium L1 Liquid phase of the first medium F2 Second medium I Interior space O Inlet for second medium O′ Outlet for second medium V Velocity field of the gaseous phase G1 

1. A heat exchanger (1) for the indirect heat transfer between a first medium (F1) and a second medium (F2), with: a shell (2) which has a shell space (3) for receiving the first medium (F1), at least one heat transfer block (4) which is arranged in the shell space (3) and enveloped by the first medium (F1) during a design-specified operation, wherein the heat transfer block (4) is designed for cooling and/or for at least partially liquefying the second medium (F2) against the first medium (F1) so that a gaseous phase of the first medium (G1) is formed in the shell space (3), wherein the at least one heat transfer block (4) is a plate heat exchanger, characterized in that for extracting the gaseous phase of the first medium (G1) from the shell space (3), provision is made for a collecting channel (5) which is located in the shell space (3).
 2. The heat exchanger as claimed in claim 1, characterized in that the heat transfer block (4) is designed so that the first medium (F1) can rise in the heat transfer block (4) during operation of the heat exchanger (1), wherein the heat transfer block (4) is especially designed for conducting the second medium (F2) in counterflow or crossflow to the first medium (F1) in the heat transfer block (4).
 3. The heat exchanger as claimed in claim 1, characterized in that a multiplicity of heat transfer blocks (4) in the form of plate heat exchangers are arranged in the shell space.
 4. The heat exchanger as claimed in claim 1, characterized in that the collecting channel (5) is connected to at least one outlet connector (6) which is provided on the shell (2) so that the gaseous phase of the first medium (G1) can be extracted from the shell space (3) through the collecting channel (5) via the at least one outlet connector (6).
 5. The heat exchanger as claimed in claim 4, characterized in that the collecting channel (5) has a wall (W) which defines an interior space (I) of the collecting channel (5) in which the gaseous phase of the first medium (G1) can flow towards the outlet connector (6), and which extends along a horizontal direction of extension (7) which stretches along an upper side (8) of the shell (2).
 6. The heat exchanger as claimed in claim 5, characterized in that the collecting channel (5) has an especially box-shaped or tubular cross section transversely to the direction of extension (7).
 7. The heat exchanger as claimed in claim 5, characterized in that the wall (W) of the collecting channel (5) has an upper side (9) and an oppositely disposed lower side (10), wherein the upper side (9) and the lower side (10) are interconnected via mutually opposite sidewalls (11) of the wall (W) of the collecting channel (5).
 8. The heat exchanger as claimed in claim 7, characterized in that one section of the wall (W) of the collecting channel (5), especially an upper side (9) of the wall (W), is formed by the shell (2).
 9. The heat exchanger as claimed in claim 7, characterized in that the lower side (10) and/or the sidewalls (11) of the collecting channel (5) have a multiplicity of especially slot-like inlet openings (12) through which the gaseous phase of the first medium (G1) can flow into the collecting channel (5).
 10. The heat exchanger as claimed in claim 4, characterized in that the collecting channel (5) has two end faces (11 a, 11 b) which lie opposite each other along the direction of extension (7), wherein the spacings of adjacent inlet openings (12) decrease towards the respective end face (11 a, 11 b).
 11. The heat exchanger as claimed in claim 7, characterized in that the lower side (10) and/or the sidewalls (11) of the collecting channel (5) have a multiplicity of especially circular inlet openings (13) through which the gaseous phase of the first medium (G1) can flow into the collecting channel (5).
 12. The heat exchanger as claimed in claim 4, characterized in that the cross section of the collecting channel (5) increases towards the outlet connector (6) so that a velocity field (v) of the gaseous phase of the first medium (G1) in the collecting channel (5) remains essentially constant with regard to value.
 13. The heat exchanger as claimed in claim 1, characterized in that the heat exchanger (1) has additional outlet connectors (6) which are interconnected via the collecting channel (5).
 14. The heat exchanger as claimed in claim 1, characterized in that the heat exchanger (1) has a large number of collecting channels (5) which are connected in each case to at least one outlet connector (6).
 15. The heat exchanger as claimed in claim 1, characterized in that the shell (2) has a cylindrical encompassing wall (14) transversely to the direction of extension (7), which interconnects the two end-face walls (15) of the shell (2).
 16. The heat exchanger as claimed in claim 4, characterized in that the at least one outlet connector (6) is arranged on the encompassing wall (W) of the shell (2), especially on an upper section, a side section or a lower section (8, 16) of the wall (14) of the shell (2), or in that the at least one outlet connector (6) is arranged on one of the end-face walls (15) of the shell (2).
 17. The heat exchanger as claimed in claim 9, characterized in that the number, distribution, size and/or shape of the inlet openings (12, 13) on the collecting channel (5) is, or are, selected so that the velocity field (v) of the gaseous phase of the first medium (G1) is established essentially uniformly with regard to value in the collecting channel (5) and especially also in the shell space (3).
 18. A heat exchanger (1) for the indirect heat transfer between a first medium (F1) and a second medium (F2), with: a shell (2) which has a shell space (3) for receiving the first medium (F1), at least one heat transfer block (4) which is arranged in the shell space (3) and enveloped by the first medium (F1) during a design-specified operation, wherein the heat transfer block (4) is designed for cooling and/or for at least partially liquefying the second medium (F2) against the first medium (F1) so that a gaseous phase of the first medium (G1) is formed in the shell space (3), wherein for extracting the gaseous phase of the first medium (G1) from the shell space (3), provision is made for a collecting channel (5) which is located in the shell space (3) and extends along a direction of extension which is oriented parallel to the longitudinal axis of the shell, and wherein the at least one heat transfer block (4) is a plate heat exchanger, and wherein the collecting channel (5) is connected to at least one outlet connector (6) which is provided on the shell (2) so that the gaseous phase of the first medium (G1) can be extracted from the shell space (3) through the collecting channel (5) via the at least one outlet connector (6), and wherein the collecting channel (5) has two end faces (11 a, 11 b) which lie mutually opposite along the direction of extension of the collecting channel (5), characterized in that the collecting channel (5) has a cross section transversely to the direction of extension (7) which increases towards the outlet connector (6) and the collecting channel (5) has a multiplicity of inlet openings (12, 13) for extracting the gaseous phase, wherein the spacings of adjacent inlet openings decrease towards the respective end face (11 a, 11 b) of the collecting channel (5).
 19. The heat exchanger as claimed in claim 18, characterized in that the heat transfer block (4) is designed so that the first medium (F1) can rise in the heat transfer block (4) during operation of the heat exchanger (1), wherein the heat transfer block (4) is especially designed for conducting the second medium (F2) in counterflow or crossflow to the first medium (F1) in the heat transfer block (4).
 20. The heat exchanger as claimed in claim 18, characterized in that a multiplicity of heat transfer blocks (4) in the form of plate heat exchangers are arranged in the shell space. 